Suche
Anzeige der Dokumente 61-70 von 77
Aufsatz
High-Purity Triggered Single-Photon Emission from Symmetric Single InAs/InP Quantum Dots around the Telecom C-Band Window
(2019-11-07)
The authors demonstrate pure triggered single‐photon emission from quantum dots (QDs) around the telecommunication C‐band window, with characteristics preserved under non‐resonant excitation at saturation, that is, the highest possible, lifetime‐limited emission rates. The direct measurement of emission dynamics reveals photoluminescence decay times in the range of (1.7–1.8) ns corresponding to maximal photon generation rates exceeding 0.5 GHz. The measurements of the second‐order correlation function exhibit, for ...
Aufsatz
Influence of the jet velocity on the weld quality of magnetic pulse welded dissimilar sheet joints of aluminum and steel
(2019-08-07)
The object of this investigation is to determine the influence of the jet velocity on the weld quality of sheet joints produced via magnetic pulse welding. The use of a suitable high‐speed camera system enables to observe the jet in detail, to determine its velocity during the collision process and to compare them to the achieved qualities (tensile strength, weld seam characteristics) of the welded samples. The results show that the quality of the weld generally correlates with the jet velocity, however the mere ...
Aufsatz
Investigation of dynamic quality changes and optimization of drying parameters of carrots (Daucus carota var. laguna)
(2019-11-29)
The effect of air temperature and sample thickness on the color changes and total carotenoids content of carrot slices was investigated. Temperature, exposure time, and moisture levels significantly affected the dynamic changes of total carotenoids and color. A slow and linear decrease in total carotenoids was observed at higher moisture content until reaching an inflection point at around 0.45 gw/gdm for all temperatures studied. Thereafter, the retention in total carotenoids decreased rapidly. The highest retention ...
Aufsatz
Interleaved Learning in Elementary School Mathematics: Effects on the Flexible and Adaptive Use of Subtraction Strategies
(2019-02-14)
Empirical findings show that students are often not capable of using number-based strategies and the standard written algorithm flexibly and adaptively to solve multi-digit subtraction problems. Previous studies have pointed out that students predominantly use the standard written algorithm after its introduction, regardless of task characteristics. Interleaved practice seems to be a promising approach to foster the flexible and adaptive use of strategies. In comparison to the usual blocked approach, in which strategies ...
Aufsatz
Toward Science-Based and Knowledge-Based Targets for Global Sustainable Resource Use
(2019-08-06)
The article discusses key aspects to be considered for the orientation of sustainable resource policies. Resource management at the local scale needs to be supplemented by governmental action in order to adjust production and consumption toward acceptable levels of global resource use. What is acceptable is being informed by scientific findings on environmental degradation and relevant cause–effect relationships. However, the desired state of the environment, the tolerable level of uncertainties about environmental ...
Aufsatz
Distributed Learning in the Classroom: Effects of Rereading Schedules Depend on Time of Test
(2019-01-09)
Research with adults in laboratory settings has shown that distributed rereading is a beneficial learning strategy but its effects depend on time of test. When learning outcomes are measured immediately after rereading, distributed rereading yields no benefits or even detrimental effects on learning, but the beneficial effects emerge two days later. In a preregistered experiment, the effects of distributed rereading were investigated in a classroom setting with school students. Seventh-graders (N = 191) reread a text ...
Aufsatz
Assessment of Flexibilisation Potential by Changing Energy Sources Using Monte Carlo Simulation
(2019-02-21)
In the fight against anthropogenic climate change, the benefit of the integration of fluctuating renewable energies (wind and photovoltaics) into the electricity grid is a widely proved concept. At the same time, a fluctuating and decentralised supply of energy, especially at lower voltage levels, leads to a local discrepancy in the power balance between generation and consumption. A possible solution in connection with demand side management is the grid-oriented flexibilisation of energy demand. The present study ...
Aufsatz
A Stapled Peptide Mimic of the Pseudosubstrate Inhibitor PKI Inhibits Protein Kinase A
(2019-04-20)
Kinases regulate multiple and diverse signaling pathways and misregulation is implicated in a multitude of diseases. Although significant efforts have been put forth to develop kinase-specific inhibitors, specificity remains a challenge. As an alternative to catalytic inhibition, allosteric inhibitors can target areas on the surface of an enzyme, thereby providing additional target diversity. Using cAMP-dependent protein kinase A (PKA) as a model system, we sought to develop a hydrocarbon-stapled peptide targeting ...
Aufsatz
X-ray imaging of a water bear offers a new look at tardigrade internal anatomy
(2019-05-11)
Background:
Tardigrades (water bears) are microscopic invertebrates of which the anatomy has been well studied using traditional techniques, but a comprehensive three-dimensional reconstruction has never been performed. In order to close this gap, we employed X-ray computed tomography (CT), a technique that is becoming increasingly popular in zoology for producing high-resolution, three-dimensional (3D) scans of whole specimens. While CT has long been used to scan larger samples, its use in some microscopic animals ...
Aufsatz
Spectral composition of low-coherence interferograms at high numerical apertures
(2019-04-11)
Interference signals in coherence scanning interferometry at high numerical apertures and narrow bandwidth illumination are spectrally broadened. This enables phase analysis within a spectral range much wider than the spectral distribution of the light emitted by the light source. Consequently, different surface features can be resolved depending on the wavelength used for phase analysis of the interference signals.
In addition, the surface topography itself affects the spectral composition of interference signals ...